Fix below warnings reported by coccicheck:
mm/swap_slots.c:197:3-9: WARNING: NULL check before some freeing functions is not needed.
Link: https://lkml.kernel.org/r/1611214229-11225-1-git-send-email-abaci-bugfix@linux.alibaba.com
Signed-off-by: Yang Li <abaci-bugfix@linux.alibaba.com>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
clear_buffer_new() is used to clear buffer new stat. When PAGE_SIZE is
64K, most buffer heads in the list are not needed to clear.
clear_buffer_new() has an enpensive atomic modification operation, Let's
add checking buffer head before clear it as __block_write_begin_int does
which is good for performance.
Link: https://lkml.kernel.org/r/1612332890-57918-1-git-send-email-zhangshaokun@hisilicon.com
Signed-off-by: Yang Guo <guoyang2@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Avoid the pointless goto out just for returning retval.
Link: https://lkml.kernel.org/r/20210122160140.223228-19-willy@infradead.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename generic_file_buffered_read to match the naming of filemap_fault,
also update the written parameter to a more descriptive name and improve
the kerneldoc comment.
Link: https://lkml.kernel.org/r/20210122160140.223228-18-willy@infradead.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't need to get the page lock again; we just need to wait for the I/O
to finish, so use wait_on_page_locked_killable() like the other callers of
->readpage.
Link: https://lkml.kernel.org/r/20210122160140.223228-17-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the got_pages label, remove indentation, rename find_page to retry,
simplify error handling.
Link: https://lkml.kernel.org/r/20210122160140.223228-16-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This simplifies the error handling.
Link: https://lkml.kernel.org/r/20210122160140.223228-15-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the complicated condition and the calculations out of
filemap_update_page() into its own function.
[willy@infradead.org: unlock page before dropping its refcount]
Link: https://lkml.kernel.org/r/20210201125229.GO308988@casper.infradead.org
Link: https://lkml.kernel.org/r/20210122160140.223228-14-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't need to give up when a non-blocking request sees a !Uptodate
page. We may be able to satisfy the read from a partially-uptodate page.
Link: https://lkml.kernel.org/r/20210122160140.223228-13-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use AOP_TRUNCATED_PAGE to indicate that no error occurred, but the page we
looked up is no longer valid. In this case, the reference to the page
will have been removed; if we hit any other error, the caller will release
the reference.
Link: https://lkml.kernel.org/r/20210122160140.223228-12-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By moving the iocb flag checks to the caller, we can pass the file and the
page index instead of the iocb. It never needed the iter. By passing the
pagevec, we can return an errno (or AOP_TRUNCATED_PAGE) instead of an
ERR_PTR.
Link: https://lkml.kernel.org/r/20210122160140.223228-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make this function more generic by passing the file instead of the iocb.
Check in the callers whether we should call readpage or not. Also make it
return an errno / 0 / AOP_TRUNCATED_PAGE, and make calling put_page() the
caller's responsibility.
Link: https://lkml.kernel.org/r/20210122160140.223228-10-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The readpage operation can block in many (most?) filesystems, so we should
punt to a work queue instead of calling it. This was the last caller of
lock_page_for_iocb(), so remove it.
Link: https://lkml.kernel.org/r/20210122160140.223228-9-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The previous patch removed wait_on_page_locked_async(), so inline
__wait_on_page_locked_async into __lock_page_async().
Link: https://lkml.kernel.org/r/20210122160140.223228-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For page splitting to succeed, the thread asking to split the page has to
be the only one with a reference to the page. Calling
wait_on_page_locked() while holding a reference to the page will
effectively prevent this from happening with sufficient threads waiting on
the same page. Use put_and_wait_on_page_locked() to sleep without holding
a reference to the page, then retry the page lookup after the page is
unlocked.
Since we now get the page lock a little earlier in filemap_update_page(),
we can eliminate a number of duplicate checks. The original intent
(commit ebded02788 ("avoid unnecessary calls to lock_page when waiting
for IO to complete during a read")) behind getting the page lock later was
to avoid re-locking the page after it has been brought uptodate by another
thread. We still avoid that because we go through the normal lookup path
again after the winning thread has brought the page uptodate.
Link: https://lkml.kernel.org/r/20210122160140.223228-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is prep work for the next patch, but I think at least one of the
current callers would prefer a killable sleep to an uninterruptible one.
Link: https://lkml.kernel.org/r/20210122160140.223228-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add filemap_get_read_batch() which returns the head pages which represent
a contiguous array of bytes in the file. It also stops when encountering
a page marked as Readahead or !Uptodate (but does return that page) so it
can be handled appropriately by filemap_get_pages(). That lets us remove
the loop in filemap_get_pages() and check only the last page.
Link: https://lkml.kernel.org/r/20210122160140.223228-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using a pagevec lets us keep the pages and the number of pages together
which simplifies a lot of the calling conventions.
Link: https://lkml.kernel.org/r/20210122160140.223228-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Increasing the batch size runs into diminishing returns. It's probably
better to make, eg, three calls to filemap_get_pages() than it is to call
into kmalloc().
Link: https://lkml.kernel.org/r/20210122160140.223228-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Refactor generic_file_buffered_read", v5.
This is a combination of Christoph's work to refactor
generic_file_buffered_read() and some of my large-page support
which was disrupted by Kent's refactoring of generic_file_buffered_read.
This patch (of 18):
The recent split of generic_file_buffered_read() created some very long
function names which are hard to distinguish from each other. Rename as
follows:
generic_file_buffered_read_readpage -> filemap_read_page
generic_file_buffered_read_pagenotuptodate -> filemap_update_page
generic_file_buffered_read_no_cached_page -> filemap_create_page
generic_file_buffered_read_get_pages -> filemap_get_pages
Link: https://lkml.kernel.org/r/20210122160140.223228-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20210122160140.223228-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, if I/O is enqueued for async execution direct paths of
generic_file_{read,write}_iter() will always revert the iter. There are
no users expecting that, and that is also costly. Leave iterators as is
on -EIOCBQUEUED.
Link: https://lkml.kernel.org/r/f5247b60e7abbd2ff850cd108491f53a2e0c501a.1610207781.git.asml.silence@gmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 74d609585d ("page cache: Add and replace pages using the
XArray") was merged, the replace_page_cache_page() can not fail and always
return 0, we can remove the redundant return value and void it. Moreover
remove the unused gfp_mask.
Link: https://lkml.kernel.org/r/609c30e5274ba15d8b90c872fd0d8ac437a9b2bb.1610071401.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 108bcc96ef ("mm: add & use zone_end_pfn() and zone_spans_pfn()")
introduced the helper zone_end_pfn() to calculate the zone end pfn. But
pagetypeinfo_showmixedcount_print forgot to use it. And the
initialization of local variable pfn is duplicated, remove one.
Link: https://lkml.kernel.org/r/20210123070538.5861-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the basic tests just validate various page table transformations
after starting with vm_get_page_prot(VM_READ|VM_WRITE|VM_EXEC) protection.
Instead scan over the entire protection_map[] for better coverage. It
also makes sure that all these basic page table tranformations checks hold
true irrespective of the starting protection value for the page table
entry. There is also a slight change in the debug print format for basic
tests to capture the protection value it is being tested with. The
modified output looks something like
[pte_basic_tests ]: Validating PTE basic ()
[pte_basic_tests ]: Validating PTE basic (read)
[pte_basic_tests ]: Validating PTE basic (write)
[pte_basic_tests ]: Validating PTE basic (read|write)
[pte_basic_tests ]: Validating PTE basic (exec)
[pte_basic_tests ]: Validating PTE basic (read|exec)
[pte_basic_tests ]: Validating PTE basic (write|exec)
[pte_basic_tests ]: Validating PTE basic (read|write|exec)
[pte_basic_tests ]: Validating PTE basic (shared)
[pte_basic_tests ]: Validating PTE basic (read|shared)
[pte_basic_tests ]: Validating PTE basic (write|shared)
[pte_basic_tests ]: Validating PTE basic (read|write|shared)
[pte_basic_tests ]: Validating PTE basic (exec|shared)
[pte_basic_tests ]: Validating PTE basic (read|exec|shared)
[pte_basic_tests ]: Validating PTE basic (write|exec|shared)
[pte_basic_tests ]: Validating PTE basic (read|write|exec|shared)
This adds a missing argument 'struct mm_struct *' in pud_basic_tests()
test . This never got exposed before as PUD based THP is available only
on X86 platform where mm_pmd_folded(mm) call gets macro replaced without
requiring the mm_struct i.e __is_defined(__PAGETABLE_PMD_FOLDED).
Link: https://lkml.kernel.org/r/1611137241-26220-3-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Reviewed-by: Steven Price <steven.price@arm.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/debug_vm_pgtable: Some minor updates", v3.
This series contains some cleanups and new test suggestions from Catalin
from an earlier discussion.
https://lore.kernel.org/linux-mm/20201123142237.GF17833@gaia/
This patch (of 2):
This adds validation tests for dirtiness after write protect conversion
for each page table level. There are two new separate test types involved
here.
The first test ensures that a given page table entry does not become dirty
after pxx_wrprotect(). This is important for platforms like arm64 which
transfers and drops the hardware dirty bit (!PTE_RDONLY) to the software
dirty bit while making it an write protected one. This test ensures that
no fresh page table entry could be created with hardware dirty bit set.
The second test ensures that a given page table entry always preserve the
dirty information across pxx_wrprotect().
This adds two previously missing PUD level basic tests and while here
fixes pxx_wrprotect() related typos in the documentation file.
Link: https://lkml.kernel.org/r/1611137241-26220-1-git-send-email-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/1611137241-26220-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memcg_data is only valid on the head page, not the tail pages. Change
the format and location of the printout within the dump to match the other
parts of struct page better.
Link: https://lkml.kernel.org/r/20210114190200.1894484-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The boot param and config determine the value of memcg_sysfs_enabled,
which is unused since commit 10befea91b ("mm: memcg/slab: use a single
set of kmem_caches for all allocations") as there are no per-memcg kmem
caches anymore.
Link: https://lkml.kernel.org/r/20210127124745.7928-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In deactivate_slab() we currently move all but one objects on the cpu
freelist to the page freelist one by one using the costly cmpxchg_double()
operation. Then we unfreeze the page while moving the last object on page
freelist, with a final cmpxchg_double().
This can be optimized to avoid the cmpxchg_double() per object. Just
count the objects on cpu freelist (to adjust page->inuse properly) and
also remember the last object in the chain. Then splice page->freelist to
the last object and effectively add the whole cpu freelist to
page->freelist while unfreezing the page, with a single cmpxchg_double().
Link: https://lkml.kernel.org/r/20210115183543.15097-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Jann Horn <jannh@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SLAB has been using get/put_online_cpus() around creating, destroying and
shrinking kmem caches since 95402b3829 ("cpu-hotplug: replace
per-subsystem mutexes with get_online_cpus()") in 2008, which is supposed
to be replacing a private mutex (cache_chain_mutex, called slab_mutex
today) with system-wide mechanism, but in case of SLAB it's in fact used
in addition to the existing mutex, without explanation why.
SLUB appears to have avoided the cpu hotplug lock initially, but gained it
due to common code unification, such as 20cea9683e ("mm, sl[aou]b: Move
kmem_cache_create mutex handling to common code").
Regardless of the history, checking if the hotplug lock is actually needed
today suggests that it's not, and therefore it's better to avoid this
system-wide lock and the ordering this imposes wrt other locks (such as
slab_mutex).
Specifically, in SLAB we have for_each_online_cpu() in do_tune_cpucache()
protected by slab_mutex, and cpu hotplug callbacks that also take the
slab_mutex, which is also taken by the common slab function that currently
also take the hotplug lock. Thus the slab_mutex protection should be
sufficient. Also per-cpu array caches are allocated for each possible
cpu, so not affected by their online/offline state.
In SLUB we have for_each_online_cpu() in functions that show statistics
and are already unprotected today, as racing with hotplug is not harmful.
Otherwise SLUB relies on percpu allocator. The slub_cpu_dead() hotplug
callback takes the slab_mutex.
To sum up, this patch removes get/put_online_cpus() calls from slab as it
should be safe without further adjustments.
Link: https://lkml.kernel.org/r/20210113131634.3671-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Qian Cai <cai@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 03afc0e25f ("slab: get_online_mems for
kmem_cache_{create,destroy,shrink}") we are taking memory hotplug lock for
SLAB and SLUB when creating, destroying or shrinking a cache. It is quite
a heavy lock and it's best to avoid it if possible, as we had several
issues with lockdep complaining about ordering in the past, see e.g.
e4f8e513c3 ("mm/slub: fix a deadlock in show_slab_objects()").
The problem scenario in 03afc0e25f (solved by the memory hotplug lock)
can be summarized as follows: while there's slab_mutex synchronizing new
kmem cache creation and SLUB's MEM_GOING_ONLINE callback
slab_mem_going_online_callback(), we may miss creation of kmem_cache_node
for the hotplugged node in the new kmem cache, because the hotplug
callback doesn't yet see the new cache, and cache creation in
init_kmem_cache_nodes() only inits kmem_cache_node for nodes in the
N_NORMAL_MEMORY nodemask, which however may not yet include the new node,
as that happens only later after the MEM_GOING_ONLINE callback.
Instead of using get/put_online_mems(), the problem can be solved by SLUB
maintaining its own nodemask of nodes for which it has allocated the
per-node kmem_cache_node structures. This nodemask would generally mirror
the N_NORMAL_MEMORY nodemask, but would be updated only in under SLUB's
control in its memory hotplug callbacks under the slab_mutex. This patch
adds such nodemask and its handling.
Commit 03afc0e25f mentiones "issues like [the one above]", but there
don't appear to be further issues. All the paths (shared for SLAB and
SLUB) taking the memory hotplug locks are also taking the slab_mutex,
except kmem_cache_shrink() where 03afc0e25f replaced slab_mutex with
get/put_online_mems().
We however cannot simply restore slab_mutex in kmem_cache_shrink(), as
SLUB can enters the function from a write to sysfs 'shrink' file, thus
holding kernfs lock, and in kmem_cache_create() the kernfs lock is nested
within slab_mutex. But on closer inspection we don't actually need to
protect kmem_cache_shrink() from hotplug callbacks: While SLUB's
__kmem_cache_shrink() does for_each_kmem_cache_node(), missing a new node
added in parallel hotplug is not fatal, and parallel hotremove does not
free kmem_cache_node's anymore after the previous patch, so use-after free
cannot happen. The per-node shrinking itself is protected by
n->list_lock. Same is true for SLAB, and SLOB is no-op.
SLAB also doesn't need the memory hotplug locking, which it only gained by
03afc0e25f through the shared paths in slab_common.c. Its memory
hotplug callbacks are also protected by slab_mutex against races with
these paths. The problem of SLUB relying on N_NORMAL_MEMORY doesn't apply
to SLAB, as its setup_kmem_cache_nodes relies on N_ONLINE, and the new
node is already set there during the MEM_GOING_ONLINE callback, so no
special care is needed for SLAB.
As such, this patch removes all get/put_online_mems() usage by the slab
subsystem.
Link: https://lkml.kernel.org/r/20210113131634.3671-3-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Qian Cai <cai@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm, slab, slub: remove cpu and memory hotplug locks".
Some related work caused me to look at how we use get/put_mems_online()
and get/put_online_cpus() during kmem cache
creation/descruction/shrinking, and realize that it should be actually
safe to remove all of that with rather small effort (as e.g. Michal Hocko
suspected in some of the past discussions already). This has the benefit
to avoid rather heavy locks that have caused locking order issues already
in the past. So this is the result, Patches 2 and 3 remove memory hotplug
and cpu hotplug locking, respectively. Patch 1 is due to realization that
in fact some races exist despite the locks (even if not removed), but the
most sane solution is not to introduce more of them, but rather accept
some wasted memory in scenarios that should be rare anyway (full memory
hot remove), as we do the same in other contexts already.
This patch (of 3):
Commit e4f8e513c3 ("mm/slub: fix a deadlock in show_slab_objects()") has
fixed a problematic locking order by removing the memory hotplug lock
get/put_online_mems() from show_slab_objects(). During the discussion, it
was argued [1] that this is OK, because existing slabs on the node would
prevent a hotremove to proceed.
That's true, but per-node kmem_cache_node structures are not necessarily
allocated on the same node and may exist even without actual slab pages on
the same node. Any path that uses get_node() directly or via
for_each_kmem_cache_node() (such as show_slab_objects()) can race with
freeing of kmem_cache_node even with the !NULL check, resulting in
use-after-free.
To that end, commit e4f8e513c3 argues in a comment that:
* We don't really need mem_hotplug_lock (to hold off
* slab_mem_going_offline_callback) here because slab's memory hot
* unplug code doesn't destroy the kmem_cache->node[] data.
While it's true that slab_mem_going_offline_callback() doesn't free the
kmem_cache_node, the later callback slab_mem_offline_callback() actually
does, so the race and use-after-free exists. Not just for
show_slab_objects() after commit e4f8e513c3, but also many other places
that are not under slab_mutex. And adding slab_mutex locking or other
synchronization to SLUB paths such as get_any_partial() would be bad for
performance and error-prone.
The easiest solution is therefore to make the abovementioned comment true
and stop freeing the kmem_cache_node structures, accepting some wasted
memory in the full memory node removal scenario. Analogically we also
don't free hotremoved pgdat as mentioned in [1], nor the similar per-node
structures in SLAB. Importantly this approach will not block the
hotremove, as generally such nodes should be movable in order to succeed
hotremove in the first place, and thus the GFP_KERNEL allocated
kmem_cache_node will come from elsewhere.
[1] https://lore.kernel.org/linux-mm/20190924151147.GB23050@dhcp22.suse.cz/
Link: https://lkml.kernel.org/r/20210113131634.3671-1-vbabka@suse.cz
Link: https://lkml.kernel.org/r/20210113131634.3671-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Qian Cai <cai@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If kmemleak is enabled, it uses a kmem cache for its own objects. These
objects are used to hold information kmemleak uses, including a stack
trace. If slub_debug is also turned on, each of them has *another* stack
trace, so the overhead adds up, and on my tests (on ARCH=um, admittedly)
2/3rds of the allocations end up being doing the stack tracing.
Turn off SLAB_STORE_USER if SLAB_NOLEAKTRACE was given, to avoid storing
the essentially same data twice.
Link: https://lkml.kernel.org/r/20210113215114.d94efa13ba30.I117b6764e725b3192318bbcf4269b13b709539ae@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix some coding style issues, improve code reading. Adds whitespace to
clearly separate the parameters.
Link: https://lkml.kernel.org/r/1612841499-32166-1-git-send-email-daizhiyuan@phytium.com.cn
Signed-off-by: Zhiyuan Dai <daizhiyuan@phytium.com.cn>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This argument hasn't been used since e153362a50 ("slub: Remove objsize
check in kmem_cache_flags()") so simply remove it.
Link: https://lkml.kernel.org/r/20210126095733.974665-1-nborisov@suse.com
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, a trace record generated by the RCU core is as below.
... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=00000000f3b49a66
It doesn't tell us what the RCU core has freed.
This patch adds the slab name to trace_kmem_cache_free().
The new format is as follows.
... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=0000000037f79c8d name=dentry
... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=00000000f78cb7b5 name=sock_inode_cache
... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=0000000018768985 name=pool_workqueue
... kmem_cache_free: call_site=rcu_core+0x1fd/0x610 ptr=000000006a6cb484 name=radix_tree_node
We can use it to understand what the RCU core is going to free. For
example, some users maybe interested in when the RCU core starts
freeing reclaimable slabs like dentry to reduce memory pressure.
Link: https://lkml.kernel.org/r/20201216072804.8838-1-jian.w.wen@oracle.com
Signed-off-by: Jacob Wen <jian.w.wen@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Delete duplicate words in fs/*.c.
The doubled words that are being dropped are:
that, be, the, in, and, for
Link: https://lkml.kernel.org/r/20201224052810.25315-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the following coccicheck warnings:
fs/ocfs2/refcounttree.c:981:16-18: WARNING !A || A && B is equivalent to !A || B.
Link: https://lkml.kernel.org/r/1612235424-80367-1-git-send-email-jiapeng.chong@linux.alibaba.com
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The error handling in this function frees "reg" but it is still on the
"o2hb_all_regions" list so it will lead to a use after freew. Joseph Qi
points out that we need to clear the bit in the "o2hb_region_bitmap" as
well
Link: https://lkml.kernel.org/r/YBk4M6HUG8jB/jc7@mwanda
Fixes: 1cf257f511 ("ocfs2: fix memory leak")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are some definitions which is not used anymore in OCFS2 module, so
as to be removed.
Link: https://lkml.kernel.org/r/2021011916182284700534@chinatelecom.cn
Signed-off-by: Guozhonghua <guozh88@chinatelecom.cn>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
iput handles NULL pointers gracefully, so there's no need to check the
pointer before the call.
Link: https://lkml.kernel.org/r/20201231040535.4091761-1-yili@winhong.com
Signed-off-by: Yi Li <yili@winhong.com>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Drop the repeated words "the" and "in" in comments.
Link: https://lkml.kernel.org/r/20210125194937.24627-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here are some of the more common spelling mistakes and typos that I've
found while fixing up spelling mistakes in the kernel since September 2020
Link: https://lkml.kernel.org/r/20210210124318.55082-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since CONFIG_EXPERIMENTAL was removed in 2013, go ahead and drop it
from any defconfig files.
Link: https://lkml.kernel.org/r/20210115010011.29483-1-rdunlap@infradead.org
Fixes: 3d374d09f1 ("final removal of CONFIG_EXPERIMENTAL")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Brian Cain <bcain@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
